I haven't played Starglider 2 for more than 20 years, but I'll take a shot at reviewing it from memory - because I did complete the game, and I still do remember quite a bit about it.

Starglider 1 was essentially a 3D shoot-em-up, with simple frame graphics. Starglider 2 really fleshed out the gameplay into a full space adventure, with multiple planets, interplanetary travel (either very very slowly, or using a warp-drive), trade deals, space pirates, and a specific end-game goal (to build a 'neutron bomb' to destroy an enemy space station, for a reason I don't think I never bothered to find out). The game came with a music cassette with an extended version of the intro song - which was a triumphant theme song that invoked the sense of adventure and danger that you might get in the game itself. I must have listened to that cassette a lot, because I still remember the song very well. (It's not bad. Do an internet search to listen to it - and imagine you're on space quest to blow up an evil space station or something.)

For the gameplay, at a basic level it's fun to just fly around and shot things - (like you might do in Starglider 1). But making it further into the game required a bit of knowledge, some exploration, discovery, and some decent piloting skills. For example, refueling the ship was no simple task - as it required carefully flying along power lines close to the ground. (An unskilled pilot would typically be bumping the ground, or crashing through the poles - doing more damage to the ship than they were getting back. And without reading the manual, you might not realise it is possible to refuel with that kind of maneuver anyway.)

Basic piloting is a challenge when starting the game. Refueling, and navigating the underground tunnels is not a simple thing for a novice. But mastering those challenges is part of what the game is about; allowing you to go to more dangerous planets further away and get a real sense of space adventure. Landing on unfamiliar planets is great (even though the planets looks a bit samey with the basic graphics, it still feels like you're somewhere new). And there are some cute touches in the space travel, such as the ship melting if you fly too close to the sun. I recall the underground tunnels as being slightly frustrating, in that you don't really know where you're going and so you just kind of fly around hoping that you find what you're looking for - and the text for the communication for the trade deals is a bit painfully slow... But the bulk of the game I think is a pretty cool experience.

Each planet had an underground base with a network of tunnels and blast-doors. Somewhere in the tunnels would be a trading base, with a trade deal particular to that planet. So aside from just flying around shooting at stuff, the main idea is that you check out the tunnels on each planet to see what they are asking for - then go find those resources (probably on some different planet or out in open space), and bring it back to make the exchange. Sometimes this is for a weapon upgrade, and sometimes it is for a component that you ultimately need to construct the neutron bomb to complete the game.

(I recall that the game manual also described a second way of refueling, by somehow using a volcano rather that the power-lines; but I don't think I ever worked that one out! So I suppose there would be still more to discover on returning to the game.)

Here are a couple of screenshots that I grabbed off the internet. The first shows the ship flying dangerously close to the ground near some of the power lines. The second is exploring one of the underground networks.